ProtobufEditor.js

  render() {
    const { classes } = this.props
    if (this.state.numCalls != 2) {
      return (<div>Loading</div>)   // Html
    }

    return (
      <Fragment>
        <Paper className={classes.root}>
          <div>Details for id {(new URL(document.location)).searchParams.get('id')}</div>
          <DescriptorWidget descriptor={this.state.descriptor} message={this.state.message} submitFn={this.submitFn} resetFn={this.resetFn} />
        </Paper>
      </Fragment>
    );
  }